I'm getting really frustrated lately every time I brew a light colored beer. With the exception of a hefe (which have been turning out pretty good) all my light beers that are lightly hopped have the same flavor. Anything with an SRM over 7-10 turns out superb.

Doesn't matter weather I use pilsner malt or basic 2-row for the base. They all seem to have a DMS type of flavor that dominates. I do 90 min boils and my IC cools really fast. They seem really thin with no head retention.

I do have very hard well water with out of sight alkalinity. But I've been using 5.2 PH buffer and conversion goes well. FGs have been what I expect. I've been using multiple generations of Wyeast 1007 for the majority of my beer styles. So maybe its mutated/infected. But that yeast (with a pilsner malt base) made an awesome american amber ale.

Where should I start looking to make a change? I'm going to start with some fresh yeast. Should I look into buying some bottled water? If so any particular suggestions as to where?